The ubiquity of cellular phones and similar mobile electronics has led to demands for ever more advanced features in these devices. Mobile phones are increasingly becoming multipurpose devices. For example, it is becoming much more common for mobile phones to include integrated devices such as cameras and alternate network interfaces (e.g., Bluetooth, Wi-Fi). Another feature that is expected to be included in many future mobile devices is the ability to determine location of the device.
Currently, location detection can be done on a coarse scale using wireless communication infrastructure, such as determining the approximate location based on the base station to which a device is connected. An even more useful form of location detection involves accessing Global Positioning System (GPS) satellites. The GPS system uses a constellation of more than two dozen satellites whose signals can be accessed by receivers on the earth. A terrestrial GPS receiver and associated logic is able to determine its latitude and longitude by triangulating the signals from three satellites. If signals from a fourth satellite can be received, the elevation can also be determined.
For some time, small GPS receiving devices have been available for such purposes as vehicle navigation, outdoor activities, location based gaming, etc. Typically, the GPS receiving devices are incorporated into a standalone device that, in its most basic form, provides a readout of current location. Where memory, displays, and processing power permit, such devices may also include other features, such as map overlays and the storage of waypoints.
As the costs of GPS sensors decrease, they are being incorporated into other devices as well. For example, modern cell phones and Personal Digital Assistants (PDAs) have become ubiquitous, general-purpose, mobile data processing devices. Given the mobility and always-on nature of such devices, it is quite natural that these devices will include GPS receivers and similar device so that the users can to take advantage of location-aware data-processing applications. For example, the currently available Nokia® N95 model cellular phone includes an integrated GPS sensor. In addition, such mobile devices are capable of accessing data networks, and this network access can enhance location-aware processing. The present disclosure describes improved location-aware methods and devices that provide advantages over existing implementations.